The present invention relates to a liquid injection apparatus including a recording head for injecting liquid.
Conventionally, a liquid injection apparatus injecting liquid by a desired method is known. For example, an inkjet recording device serving as a liquid injection apparatus injects ink, which is liquid, from a plurality of nozzles formed in the recording head, thus forming an image such as a character on a recording surface.
To ensure a smooth operation of the recording head, a cap is pressed against a nozzle forming surface (a liquid injecting surface) of the recording head in order to define a sealed space. This prevents the recording head from becoming dry and from being contaminated by, for example, dusts.
For example, Japanese Laid-Open Patent Publication No. 2001-26113 discloses a liquid injection apparatus having a cap movable toward the recording head. To assure that the cap is reliably placed in tight contact with the nozzle forming surface, the cap is guided along a slanted surface of a guide extension in a sliding manner. The cap is thus positioned with high accuracy.
In this liquid injection apparatus, the recording head is reciprocated in a horizontal direction, while the cap is moved upward. However, for example, if the recording head is moved horizontally with the cap maintained in tight contact with the nozzle forming surface, the sealed space cannot be maintained. Further, the cap or recording head may be damaged. To avoid the problem, the liquid injection apparatus employs a mechanism for separating the cap from the recording head when the recording head moves.
The liquid injection apparatus starts to move the recording head for detecting the position of the recording head, for example, when the device is turned on. At this stage, the cap must be separated from the recording head. However, as above described, the recording head must be protected from dryness and contamination. Therefore, when the recording head is stopped, it is preferred that the cap maintain the liquid injecting surface of the recording head in a sealed state for avoiding the exposure to the ambient air.
In addition, for example, Japanese Laid-Open Patent Publication No. 2000-255075 discloses an inkjet recording device having a maintenance unit 1000, as illustrated in FIGS. 25 to 27. The maintenance unit 1000 automatically cleans the recording head. The maintenance unit 1000 includes a carriage 1040, a recording head 1050, and a non-illustrated wiping member. The recording head 1050 is formed in the carriage 1040. The wiping member is formed from, for example, an elastic material. The wiping member wipes ink from a nozzle forming surface of the recording head 1050. Alternatively, the ink may be drawn from and discharged from a nozzle of the recording head 1050 as needed. This structure maintains a preferable communication between an ink passage and the opening of the nozzle. With the maintenance unit 1000, the inkjet recording device decreases the incidence of insufficient ink injection caused by clogging of the nozzle.
With reference to FIG. 25, the maintenance unit 1000 has a cap unit 1030 rotationally supported by a base 1010 through an arm 1020. The cap unit 1030 includes a cap 1060 that seals the recording head 1050. The cap unit 1030 also includes a pair of capping guide extensions 1070 for guiding the recording head 1050 and a pair of flushing guide extensions 1080, which are formed at opposing sides of the cap 1060. The guide extensions 1080 are axially larger than the capping guide extensions 1070.
A contact piece 1090 is formed in the carriage 1040. A flag piece 1100 and a projection 1110 are formed in, the cap unit 1030. When the carriage 1040 moves rightward as viewed in FIG. 25 and the contact piece 1090 contacts the flag piece 1100, the projection 1110 also moves rightward as guided by a guide 1120 formed in the base 1010. The cap 1060 thus opposes the recording head 1050 of the carriage 1040 as shown in FIG. 26. At this stage, the recording head 1050 contacts the flushing guide extensions 1080. This arrangement forms a clearance L between the recording head 1050 and the cap 1060. In this state, the recording head 1050 is located immediately above the cap 1060 and is permitted to perform flushing.
If the carriage 1040 moves further rightward from the state of FIG. 26, the arm 1020 is pivoted, as shown in FIG. 27. The recording head 1050 is guided by the capping guide extensions 1070, and the cap 1060 contacts the recording head 1050. This seals the recording head 1050 from the exterior.
This configuration regulates the position of the recording head 1050 to the position at which the cap 1060 reliably receives the ink discharged through flushing. Further, when capping is performed, the recording head 1050 and the cap member 1060 are reliably positioned relative with each other with high accuracy.
When flushing is performed, the recording head 1050 contacts the flushing guide extensions 1080, as illustrated in FIG. 26. The contact may cause an impact that generates a noise. Further, with reference to FIG. 27, when the recording head 1050 is sealed from the exterior, the recording head 1050 contacts the capping guide extensions 1070. Also in this case, the contact may cause an impact generating a noise. It is thus difficult to provide an inkjet recording device that operates silently as long as the device includes the maintenance unit 1000.
In addition, in order assuredly form the clearance L for flushing, the maintenance unit 1000 must be provided with the flushing guide extensions 1080. This structure limits the layout of the maintenance unit 1000.